scholarly journals The Mark IV VLBI Data-Acquisition and Correlation System

1993 ◽  
Vol 156 ◽  
pp. 151-157
Author(s):  
Alan R. Whitney
Keyword(s):  
Data Acquisition ◽  
Cost Effective ◽  
Data Acquisition System ◽  
Data Rate ◽  
Acquisition System ◽  
The Past ◽  
Vlbi Observations ◽  
Data Rates ◽  
Correlation System ◽  
Vlbi Data

Modern VLBI observations for both astronomy and geodesy continue to demand the utmost in sensitivity. Of the methods potentially available for increasing the sensitivity of continuum VLBI observations, increasing the recorded bandwidth is generally the most cost effective.Over the past two years a broadly-supported program has been underway at Haystack Observatory to increase the sensitivity of the Mark IIIA VLBI system by more than a factor of 2. The result is an upgrade to the existing Mark IIIA data-acquisition system, dubbed Mark IV, which increases the maximum data rate to 1024 Mbits/sec, more than quadrupling the maximum data-rate of the Mark IIIA.A new correlator, based on a new custom VLSI correlator chip is also being designed to support the 1 Gbit/sec data rates from the Mark IV data-acquisition-system. An international collaborative effort is being mounted to help defray the high costs of development.

scholarly journals VLBI Observations of the Gravitational-Lens Images of Q0957+561

1984 ◽  
Vol 110 ◽  
pp. 243-246
Author(s):  
M. V. Gorenstein ◽  
I. I. Shapiro ◽  
N. L. Cohen ◽  
R. J. Bonometti ◽  
E. E. Falco ◽  
...  
Keyword(s):  
Time Delay ◽  
Data Acquisition ◽  
Mass Distribution ◽  
Data Acquisition System ◽  
Gravitational Lens ◽  
Acquisition System ◽  
Vlbi Observations ◽  
Vlbi Data ◽  
Cosmological Constants

We have conducted a series of VLBI observations of the gravitational-lens images of the quasar Q0957+561 (Walsh et al., 1979), utilizing the Mark III VLBI data acquisition system (Rogers et al., 1983). The goals of our observations are to (1) map the milliarcsecond structure of the A and B images, (2) detect the predicted third image of the quasar, and (3) determine the time delay between the images. We will use these results to constrain the mass distribution of the lens and, possibly, cosmological constants.

Inter and Intrablade Row Laser Velocimetry Studies of Gas Turbine Compressor Flows

1988 ◽  
Vol 110 (3) ◽  
pp. 369-376 ◽  
Author(s):  
M. C. Williams
Keyword(s):  
Data Acquisition ◽  
Gas Turbine ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Fan Studies ◽  
Data Rates ◽  
Recorded Data ◽  
Multistage Compressor ◽  
Gas Turbine Compressor

Characterization of the aerodynamics of the flows within gas turbine intrablade passages requires the development of sensitive laser-Doppler velocimeters, a data acquisition system capable of efficiently and accurately handling substantial quantities of data, and appropriate methods of posttest data analysis and display to maximize the value of the recorded data. Pratt & Whitney developed a confocal LDV and data acquisition system that were first employed in the mid-1970s for gas turbine intrablade fan studies. Experience gained through use of the instruments in several aerodynamic studies has provided the basis for the development of a second generation system. The performance of the recently enhanced instrument configured as a single-component LDV has been demonstrated by a NASA-sponsored fan study in which approximately 200 million valid velocity signals were rapidly acquired. The high resolution and data rates achieved permitted detailed mappings of the flow at a variety of conditions and locations. Following this successful study, a second NASA-sponsored program was initiated to assess the feasibility of utilizing this LDV capability to perform detailed stator–rotor interaction studies in a multistage compressor. The equipment employed in these studies will be described and data typical of the findings will be presented.

scholarly journals Infrared Arrays at the European Southern Observatory

1995 ◽  
Vol 167 ◽  
pp. 81-92
Author(s):  
G. Finger ◽  
G. Nicolini ◽  
P. Biereichel ◽  
M. Meyer ◽  
A. F. M. Moorwood
Keyword(s):  
Data Acquisition ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Large Format ◽  
High Data ◽  
Array Detectors ◽  
Very Large Telescope ◽  
Data Rates ◽  
Array Camera ◽  
Infrared Array

This paper gives an overview of infrared array detectors which have been tested and used at ESO. The performance of arrays using Reticon type readouts, CCD readouts and switched FET multiplexers have been evaluated for both InSb and Hg1−xCdxTe detectors. Performance limitations specific to the NICMOS3 256 × 256 Hg1−xCdxTe detector installed in the ESO infrared array camera IRAC2 are addressed. The first test results with a high well capacity SBRC 256 × 256 InSb array are also presented.Advanced readout techniques for image sharpening tested on a 2.2-m telescope are discussed briefly. A new generation of instruments being built for the VLT, the very large telescope project of ESO, is designed to house large format 1024 × 1024 IR arrays. A fast data acquisition system is currently being developed at ESO. The system is capable of handling the high data rates generated in the thermal infrared by large format low well capacity arrays. It can also cope with the low read noise required for flux levels of ≤ one photon/sec. It will first be installed in ISAAC, the Infrared Array Camera and Spectrometer built for the VLT (Moorwood 1993). The present status of both the detector developments and the data acquisition system is reviewed.

Portable cost-effective EEG data acquisition system

2011 ◽  
Vol 35 (3-4) ◽  
pp. 185-190 ◽  
Author(s):  
N. Agarwal ◽  
M.S. Nagananda ◽  
S. M. K. Rahman ◽  
A. Sengupta ◽  
J. Santhosh ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Cost Effective ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Eeg Data

Development of Compact, Cost-effective, FPGA-Based Data Acquisition System for the iPET System

2017 ◽  
Vol 37 (6) ◽  
pp. 858-866 ◽  
Author(s):  
Eungi Min ◽  
Kwangdon Kim ◽  
Hakjae Lee ◽  
Hyun-Il Kim ◽  
Yong Hyun Chung ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Cost Effective ◽  
Data Acquisition System ◽  
Acquisition System

scholarly journals K-4 VLBI Data-Acquisition System

1997 ◽  
Vol 49 (6) ◽  
pp. 699-708 ◽  
Author(s):  
Hitoshi Kiuchi ◽  
Jun Amagai ◽  
Shin'ichi Hama ◽  
Michito Imae
Keyword(s):  
Data Acquisition ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Vlbi Data

scholarly journals High speed wireless data acquisition system

2021 ◽  
Author(s):  
Muhammad Nadeem
Keyword(s):  
Data Acquisition ◽  
High Speed ◽  
Sampling Rate ◽  
Data Gathering ◽  
Data Acquisition System ◽  
Data Rate ◽  
Acquisition System ◽  
Wireless Data ◽  
Wireless Data Acquisition ◽  
Central Data

In a setup for a system long term stability and reliability test, sensors are used to measure physical quantities, affecting the behavior of the system, by sampling the sensor readings, convert it to digital numerical value and saving it for further detail analysis. The sensors are wired to a central location to collect and log data, due to extensive wiring requirements the setup is very difficult and sometimes even impossible to implement. This project presents an implementation of high speed wireless data acquisition system which samples sensors output at high speed (5 KHz), converts it to digital numerical form and sends wirelessly to central data gathering unit thus avoiding home run wiring from each sensor to central data gathering unit where it is logged on USB flash drive and send to PC for real time display. The implementation target was wireless link between a transmitter module, serving a maximum of 8 sensors at 5 KHz sampling rate and 16bit ADC resolution for each sensor, to data gathering unit. The implementation does fall short on specification on number of channels and sampling rate due to limitation of over the air data rate of the radio module, what we were able to achieve is 4 channels of 16 bit ADC resolution at 2 KHz sampling rate using radio module with 300 Kbps over the air data rate. Using different sensors and with different configurable settings the tests shows that the stored data at the data gathering unit and the data stored using wired data acquisition system has no difference. For future improvement radio module with over the air data rate (1.55 Mbps) which allows multiple transmitters connected wirelessly to a single data gathering unit providing more flexibility in sensor deployment. Even though the implementation falls short on some of the features but with using improved radio module and/or using some compression techniques on ADC data, before sending data wirelessly, these short comings could be overcome easily.

Sign in / Sign up

Export Citation Format

Share Document